Hitherto, various airbag devices, such as a driver airbag device that is inflated for deployment towards a driver from a rotational center of a steering wheel at a driver's seat, and a passenger airbag that is inflated for deployment towards a passenger's seat from an instrument panel, are used for restraining the body of an occupant when, for example, an automobile collides.
In recent years, an airbag device has already been proposed (refer to, for example, Patent Document 1) to overcome the following. That is, when a serious accident that applies a large external force to an automobile occurs, for example, overturning of a vehicle body, resulting from a collision, or falling of a heavy object, such as a tree, a shock may be applied to the head of an occupant from thereabove due to the shock generated during the serious accident.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2005-37011